The 38-year-old victim suffered an injury to his neck and was taken to Queen Alexandra Hospital, in Cosham, where his condition is described as critical.

As a result of this incident, several roads in the area are currently closed to allow officers to carry out investigation work.

St Mary’s Road from Woodlands Street and parts of Kingston Road and Lake Road itself are all closed to traffic and pedestrians. Fratton Road was reopened around 7.45am this morning.

A spokesman said: ‘We understand that these closures will cause significant inconvenience to those living and working in the area and we would like to apologise for that and thank people for their patience.